Meanders and Ox-bow lakes

Meanders are bends in the river, they usually occur on floodplains where the river has room to develop bends.

The inside of a meander bend has shallower water and material is deposited there forming a slip-off slope. The slowest flow is on the inside.

On the outside of the meander bend, erosion occurs. The water is deep and the fastest flo is there. A river cliff forms when the bank is undercut by erosion.

Erosion on the outside and deposition on the inside cause a meander bend to change over time. The fastest flow will now be straight down the river and deposition cuts the meander off from the river forming an ox-bow lake (the river cuts through its neck).

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drainage basin

Drainage basin - the area of land drained by a river and its tributaries.

Waterfalls and gorges

Waterfalls form when there is a difference in underlying rock. the softer rock is worn away more quickly and the harder rock is undercut. The overhanging harder rock will become unsupported and collapse. The rock will fall into the irver and be swirled around forming a plunge pool. Spray action erodes the softer rock and the process repeats many times. Each time the waterfall retreats upstream creating a gorge.

long term and short term effects of floods & Preve

Soft engineering - gravel placed on river bed in upper course to make it flood before it gets to town, afforestation to increase interception, trash screens, pre-clearance of trees, demountable flood barriers